Chanos warns of China risk as Alibaba begins trade

Short seller Jim Chanos gave a presentation Friday warning of risks to China's economy, raising questions about stock valuations just as Chinese e-commerce giant Alibaba set a record for the largest-ever initial public offering.

In a 30-page presentation obtained by CNBC.com, Chanos, of Kynikos Associates, says the stock market is "no longer cheap" and that "China global risk" is increasing.

At least one attendee tweeted that Chanos spoke specifically about Alibaba, saying, "quick little thought about Ali Baba: everyone forgets that he was a thief." Chanos reportedly also said that Alibaba's true margins may be "hard to know."

A spokesman for Alibaba declined to comment, but the company's prospectus itself mentions a potential slowdown in the Chinese economy as an explicit risk factor.

Chanos' comments came within minutes of Alibaba's first trade on the New York Stock Exchange. The IPO, which raised nearly $22 billion, priced the night before at $68 a share and began trading sharply higher at $92.70. In late trade, Alibaba changed hands at $92.65.

Chanos' presenation outlined a series of familiar issues he has raised about China, including excessive bank risks and frothy real estate markets.